Building an svxLink station

Components

• Raspberry Pi Zero 2W (currently hard to find, but potentially available on Amazon, ebay, Adafruit, Digi-Key)
• ReSpeaker 2-Mics wm8960 Pi HAT (Amazon, Seeed Studio)
• Class 10 micro SD card (Amazon, Target, Wal-Mart, etc.)
• 8 ohm Speaker w/mating connector for ReSpeaker board (Digi-Key, All Electronics, Amazon, etc.)
• Enclosure (optional)

Preparation

• Download the Raspberry Pi “Buster” operating system ISO image
  • URL: https://www.raspberrypi.com/software/
  • Raspberry Pi Imager can be used to create the bootable operating system for your Pi
• Create a “wpa_supplicant.conf” file and copy this to the “boot” partition
  • Instructions for doing this can be found using a Google search.
• Create an empty regular text file named “ssh” in the root of the “boot” partition – this can be done via Linux or MacOS using the “touch” command.
  • This enables the ability to remotely log into the system over the network using “ssh”.
• Install your newly created SD card into your Raspberry Pi Zero W (or 2W) and connect the power cable
• Once the system has completed booting, use an ssh client to log into the system as the “pi” user with the password “raspberry”
  • To determine the IP address of your Pi, you can often find it through your routers web interface or use a utility like “nmap”.
  • If you’ve got a USB keyboard, mouse, and monitor attached, you don’t need to worry about the IP address for now. You can find it using “ifconfig -a”
• Update the operating system using the commands:
  • apt -y update && apt -y upgrade
• Change the password for the “pi” and “root”users
  • sudo -i
  • passwd root
  • passwd pi
• Confirm raspberry pi is operating normally and the network is accessible

Installing & Configuring svxLink

• Either open a shell window (Accessories -> Terminal) via the Desktop or ssh into the Pi using putty (Windows) or ssh (Mac/Unix)
• Download my installation script:
  • wget -q https://nj6n.com/svxlink/respeaker_svxlink
• Confirm it was downloaded by viewing with “more”
  • more respeaker_svxlink
• Execute the installation script
  • bash respeaker_svxlink
• This will take some time while the WM8960 driver and svxlink software is downloaded, compiled, and installed.
• The installation script should finish with a message indicating you should reboot the system:
  • sudo reboot

• ssh back in (or open Terminal again) and make sure the recording and playback devices are now present:

pi@raspberrypi:~$ aplay -l

**** List of PLAYBACK Hardware Devices ****
card 0: seeed2micvoicec [seeed-2mic-voicecard], device 0: bcm2835-i2s-wm8960-hifi wm8960-hifi-0 [bcm2835-i2s-wm8960-hifi wm8960-hifi-0]
Subdevices: 1/1
Subdevice #0: subdevice #

• If the card is not at “DEV=0”, you will need to change the [Rx1] and [Tx1] settings in the /etc/svxlink/svxlink.conf for: “AUDIO_DEV=alsa:plughw:0″
• Now you’re ready to test your Respeaker based svxlink station
• First determine if svxlink is running or not.
  • sudo systemctl status svxlink
  • “Active: active (running)” means it’s running
  • “Active: inactive (dead)” means it’s not running
• If it is running, you can stop the process from running:
  • sudo systemctl stop svxlink
• You can manually start svxlink by simply typing:
  • svxlink
• This is useful for testing. You can quickly determine if the configuration has loaded “SimplexLogic” properly or not.
• You can test the audio output by typing “*#”
• Exit svxlink by typing “q”
• Start the background process for svxlink back up:
  • sudo systemctl start svxlink

• To adjust audio levels, use the sudo alsamixer command in a shell window. The audio you hear (transmit audio) can be adjusted through the “Speaker” and “Playback” settings.
• To adjust receive audio level, Press and use the right arrow key to select the CAPTURE device. Use up/down arrows to adjust levels.
  • NOTE: If there is NO device with the word “CAPTURE” under it, you can select the capture device by arrowing over to it and pressing the space bar.
• Press the escape key to exit. 
• To save your adjustments, use the following command:
  • sudo alsactl store -f /etc/wm8960-soundcard/wm8960_asound.state
• Svxlink creates a system log that you can monitor:
  • sudo tail -f in /var/log/svxlink
• The configuration file for svxlink is in /etc/svxlink/svxlink.conf
• To Configure EchoLink:
  • vi /etc/svxlink/svxlink.d/ModuleEchoLink.conf